1. Field of the Invention;
The present invention relates to a locus correcting method for industrial robots.
2. Description of the Related Art
In industrial robots, it is known to preliminarily teach a movement locus (target movement locus) that a work point of a robot should follow during operation by using a fixed coordinate system such as a work coordinate system set for a subject to be processed by the robot or a base coordinate system set for the robot body, and effect playback control of the robot to move the work point of the robot along the target locus. However, during execution of the work, if the position of the subject of work is deviated from the setting position thereof at the time of teaching, the taught locus is also deviated from the target locus. In this case, there occurs a deviation of the actual locus of the work point from the target locus even though the work point is moved exactly along the taught locus, thus making the work inaccurate. Conventionally, when such a deviation occurs, a deviation in the fixed coordinate system is detected and the position of the work point is corrected such that the actual locus coincides with the target locus. However, to detect a deviation in the fixed coordinate system, a sensor system must be constructed so as to cover the entire work region of the robot. Further, when the position of the subject of work is moved frequently during the work, the position of the work point must be corrected each time the subject is moved, whereby the load of information processing of the robot is increased.